(7:30 p.m. EDT) -- Savvy travelers know that the first thing to do when renting a car is to check the bumper for existing dings and dents, less they be "dinged" for them when returning their vehicles. But, should passengers exercise the same caution when walking into their cruise cabins on embarkation day?

If you don't, you should probably start -- a lesson Carnival passenger Chris Harvey learned the hard way. According to a blog entry on his company's Web site, squaremouth.com, Harvey and his family were recently detained aboard Carnival Freedom for several hours on disembarkation morning, wrongly accused by their room steward for having scuffed up a desk -- and subsequently banned for life from sailing on any Carnival ship in the future.

For Harvey, the trouble started when he, his wife and two children -- ages 8 and 4 -- were waiting to debark after a nine-night Eastern Caribbean voyage from Ft. Lauderdale. They were summoned to return to their cabin, where their room steward pointed out the damage, suggesting they had used the edge of the desk to open a beer bottle. (Harvey points out that the empty Bud Lite in the cabin featured a screw top -- not to mention the fact that all beers are given to passengers already opened.)

When the Harveys refuted the steward's claims, higher ranking staff, including security personnel, stepped in -- all of whom refused to entertain the possibility that the Harveys weren't responsible for the damage. "They were all lovely, which was what made it all the more strange," Harvey tells us, using the analogy of a friendly tech support representative who won't veer off a script. "I said, 'We are never going to admit to something we didn't do. Just escalate this to where it's going to go.' In the end, they said, 'Here's your choice, admit it or be banned for life.'"

Because the Harveys refused to take responsibility for the damage, they agreed to sign off on the ban. Staff left to prepare paperwork. When no one came back to the cabin after 20 minutes, the Harveys decided to debark -- but when they swiped their key cards, security whisked them to guest services (a move generally reserved for those who haven't paid their onboard bills).

Harvey says it took another full hour to move into a security office where they sat while the crew typed up a letter, which they were required to sign before leaving the ship. They were the last passengers to walk off.

St. Petersburg Times' reporter Steve Huettel happened to spot Harvey's blog on September 2 and called both Harvey and Carnival for each party's side of the story. Within an hour of those conversations, Harvey received a call from Carnival spokeswoman Jennifer De La Cruz, who apologized on behalf of the line and repealed the ban.

This clearly disturbing tale raises a question of a broader issue than Harvey's experience with Carnival. The rules for auto renters are pretty clear, with monetary penalties spelled out for charges such as dented fenders, broken windshield wipers and tears in upholstery while tire erosion and oil loss would be considered normal wear and tear. But what are the rules when it comes to cruising?

Obviously, a passenger who causes severe destruction in his or her stateroom, or who lights up a cigarette in a cabin that's clearly smoke-free, should pay the price. But are travelers considered liable for normal wear and tear? If you nick a dresser with your hairdryer or scuff a wall with your suitcase, will you have to pay up?

At this point, only one of the cruise lines we contacted for guidance gave us an answer. Norwegian Cruise Line spokeswoman Courtney Recht tells us that there's no official policy as these situations are handled on a case by case basis, but notes that guests are normally charged when there's "considerable" damage that requires items to be replaced -- holes in walls, broken furniture, damaged art, burned carpets or linens (not normal wear and tear).

A spokesperson for Royal Caribbean did not respond to our query. Contacts at Princess and Carnival weren't immediately able to answer questions about their policies, though Carnival did provide a statement about Harvey's case, saying that senior management will be "examining what transpired to ensure that guidelines for what warrants this type of action are clearly defined onboard the vessels."

We'll update you as we learn more. In the meantime, have you ever been required to pay for damages? Do you think Carnival handled Harvey's situation appropriately? How will you avoid a similar fate in the future? Tell us here.